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The Bacteroides species are important micro-organisms, both in the normal physiology of the intestines and as frequent opportunistic anaerobic pathogens, with a deeply-rooted phylogenetic origin endowing them with some interesting biological features. Their prevalence in anaerobic clinical specimens is around 60%-80%, and they display the most numerous and highest rates of antibiotic resistance among all pathogenic anaerobes. In these antibiotic resistance mechanisms there is a noteworthy role for the insertion sequence(IS) elements, which are usually regarded as representatives of ‘selfish’ genes; the IS elements of Bacteroides are usually capable of up-regulating the antibiotic resistance genes. These include the cep A(penicillin and cephalosporin), cfx A(cephamycin), cfi A(carbapenem), nim(metronidazole) and erm F(clindamycin) resistance genes. This is achieved by outwardoriented promoter sequences on the ISs. Although some representatives are well characterized, e.g., the resistance gene-IS element pairs in certain resistant strains, open questions remain in this field concerning a better understanding of the molecular biology of theantibiotic resistance mechanisms of Bacteroides, which will have clinical implications.
The Bacteroides species are important micro-organisms, both in the normal physiology of the intestines and as frequently opportunistic anaerobic pathogens, with a deeply-rooted phylogenetic origin endowing them with some interesting biological features. Their prevalence in anaerobic clinical specimens is around 60% - 80%, and they display the most numerous and highest rates of antibiotic resistance among all pathogenic anaerobes. Among these antibiotic resistance mechanisms there is a noteworthy role for the insertion sequence (IS) elements, which are usually considered as representatives of representatives of ’selfish’ genes ; the IS elements of Bacteroides are usually capable of up-regulating the antibiotic resistance genes. These include the cep A (penicillin and cephalosporin), cfx A (cephamycin), cfi A (carbapenem), nim (metronidazole) and erm F This is achieved by outwardoriented promoter sequences on the ISs. This is achieved by outwardoriented promoter sequences on the ISs. nce gene-IS element pairs in certain resistant lines, open questions remain in this field concerning a better understanding of the molecular biology of theantibiotic resistance mechanisms of Bacteroides, which will have clinical implications.